This invention relates to liquid transfer devices used in laboratories, and more particularly, is directed toward a multi-channel pipetting device which enables the user to adjust the spacings between pipette tips.
Pipetting systems are used in laboratories for the transfer of relatively small quantities of liquids. The liquid is normally drawn into the tips by suction and is subseguently released into the wells of microtiter plates or other receptacles. Frequently the transfer involves patient samples which are moved from one set of receptacles to another of different spacing. Because virtually all hand operated multi-channel pipettes have a fixed spacing between pipette tips, the transfer must be made by single channel pipettes, which is a slow and very inefficient process. Some large laboratories and pharmaceutical firms which perform thousands o transfers a day have purchased fully automatic robotic systems that cost tens or hundreds of thousands of dollars, but those systems are beyond the reach of small and medium size firms.
One important object of this invention is to provide a pipetting system which is relatively inexpensive but which is capable of being adjusted to vary the spacing between the pipette tips so that liquid may be transferred from one set of receptacles to another set of different spacing.
A more specific object of the present invention is to provide a pipetting system that enables the user with a simple manipulation to move the pipette tips from one set of spacings to another.
It is a further object of the present invention to provide a pipetting system which allows the fittings that carry the pipette tips to be adjusted simultaneously between two standard spacings of the receptacles.
Another important object of the present invention is to provide a hand-held expandable pipetter that can easily be customized during manufacturing to establish two preselected settings for the fittings of the pipetter, which support the pipette tips.
It is a further object of the present invention to provide a pipetting system that is of simple construction and therefore relatively inexpensive to manufacture.
It is a further object of this invention to provide a pipetting system that is easy to operate and does not require complicated adjustments for use.
It is a further object of the present invention to provide a hand-held pipetter having a tip removing assembly that remove tips safely and efficiently regardless of the positions of the tips and their fittings on the pipetter.
It is a further object of the present invention to provide a pipetting system having a tip removing assembly that requires a minimum force to remove the tips.
The system is embodied in a boot-shaped instrument having a housing with a handle section and a foot or lower section. A plurality of fittings aligned in a row extend downwardly from the foot, and a manually operated mechanism within the foot is attached to the fittings to enable a user to vary the spacing between them. The mechanism includes a rod attached to the fitting at one end of the row, and all the fittings are attached to on another by a flexible strap. The rod extends out of the foot and carries a knob to facilitate its actuation. By moving the rod between its extreme positions the row of fittings are moved between contracted and expanded positions established by the length of the strap and the mountings that slidably carry the fittings on the foot.
A tip removing mechanism operated by a trigger on the handle section has a stripper that can remove the disposable tips from the fittings regardless of the spacing of the fittings. As the trigger is squeezed, the stripper pushes the tips off the fittings. In order to reduce the overall force required to eject the tips the ejecting surface of the stripper is stepped so that groups of tips are engaged in sequence causing first one group and then another to be pushed off the fittings.
The many objects and features of this invention will be better understood and appreciated from the following detailed description of the preferred embodiment thereof read in connection with the accompanying drawings.